Cold water dispersible laundry starch



United States QOLD WATER DISPERSIBLE LAUNDRY STARCH Walter J. Katzbeck, Oak Park, 112., assignor to Corn Products Company, a corporation of Delaware No Drawing. Filed June 10, 1957, Ser. No. 664,509 2 C iaim s. (Cl. 106-410) This invention relates to a powdered starch concentrate which can be used in the preparation of ready-to-use laundry starches and other textile sizes. 7

Various preparations of starch for home laundry are available, and of particular interest are those which require no cooking prior to use. A large percentage of the ready-muse products are the so-called liquid laundry starches. While these have the advantage of being easy to use, there are certain inherent disadvantages connected with their use as well as in their manufacture.

The consumer finds it inconvenient to carry home from the market a heavy bottle and a relatively large amount or water while paying a relatively high price for aproduct which, in comparison to a freshly prepared starching solution prepared by cooking starch in the home, has only approximately the same stifiening power. Also many of the commercially available liquid laundry starch products contain water ionizable salts. These, due to electrolytic action in contact with bimetallic elements, such as the commonly encountered Talon fasteners in clothing, cause fabric weakening and, ultimately, holes in clothing.

The manufacturer of liquid laundry starches finds the use of a nonreturnable glass container to package the product expensive, and freight costs for transporting an aqueous product except for short distances are high. Losses due to breakage are incurred during shipment and storage, especially at below freezing temperatures.

To overcome these several disadvantages and retain the desirable features of a liquid laundry starch product, an obvious improvement would be .to supply the consumer with a dry, powdered product containing starch which is readily water dispersible. The consumer can shake-up such a product with water inthe homeland, without cooking, produce a liquid starch stock solution which .is the equivalent of the precooked liquid starches she purchases on the market.

However, prior to my discovery, no known starch product has been satisfactory in all respects for such a purpose. Uncooked starches dispersedlin water do not remain in suspension but pack down into a semisolid mass which is almost impossible to redisperse by shaking. Starch products which require cooking for preparation are not convenient to the consumer. Pregelatinized and dried starch products offering stiffening power equal to commercial liquid laundry starches are knownbutdo not disperse readily in water and the product causes masking, flaking and streaking on cloth and-sticking to the iron when used by the consumer. A pregelatinized, -dried product, such as described under U.S. Patent- 2,609,326, is freely dispersable in water but has been converted to such an extent that it possesses'a relatively low degree of stiffening power and would-not form a conventional liquid laundry starch product. In any event, no starch or starch product now known is available which can be shaken with water to produceianaqueous ,productwhich is stable and has the appearance and properties of a freshly prepared starching solution which the consumer expects.

The main object of this invention is to provide a dry 7 percent.

2,9383% Patented May 31, 1950 2 powdered starch concentrate which is readily dispersible in'cold water and can be used to produce a liquid laundry starch stock solution which has equivalent sizing power to commercially available precooked liquid laundry starches and to freshly prepared cooked laundry starches. Other objects will appear hereinafter.

I have made the unexpected discovery that when a waxy. type of' starch is treated slightly with an oxidizing agent so as not to significantly reduce the stiifening power of the original starch'but sufficiently to produce a prodnot which has high clarity, and when this product is prepasted inwater containing various salts or acids, such as boric acid and boraxor mixtures thereof, and optionally, coloring agents, perfumes,'germicidal agents, etc., and the paste is dried by conventional means to produce a flake, then the ground product is freely dispersible when shaken with water for approximately 5 seconds and it forms a full-bodied, permanent starch stock solution. This starch solution is comparable to commercial liquid laundry starches on the market in respect to stiffening power and ironing characteristics and is equivalent to freshly prepared laundry starch.

The starch should be of the waxy type, e.g., waxy grain sorghum, waxy maize, waxy rice, and the like, and the amount of oxidation is critical although various methods of oxidation of the starch 'may be used. The starch should be oxidized only to the extent where it has a carboxyl concentration which falls within the range of 0.025 to 0.12 percent. It will then have a Scott viscosity which falls within the range of 40 to l2O seconds per 100 ml. on the basis of 12 grams of starch cooked in 280 ml. of water for 15 minutes and within the range of 25 to 90 seconds per 100 ml. when cooked for 90 minutes. The paste obtained from the Scott viscosity determination is placed in a 13 mm. cell and cooled to ,80 F. and will have a clarity expressed as percent light transmission against distilled water which falls within the range of to 95 percent using 13 mm. cuvettes in a Model 14 Coleman spectrophotometerat a wavelength of 650m The starch will have a Barbender hot paste viscosity which .fallslwithin the range of 50 to 350 units at a temperature "the starch gela'tiniz'ed, dyes, germicidal agents, etc., then may be added and the resultant'paste'dried, as by roll or spray drying. The amount of" salt or acid may range from 5 to 20 percent of the starch, dry substance. The dried product produced after grinding has a funnel dis- .persibility as defined later which falls within the range of 70 to 1300 seconds per 200 ml. when 10 grams of the product are dispersed in 400 ml. of water at F., Brabender hydration characteristics which fall within the following ranges: peak viscosity 50 to dtltlunits; time to reach peak viscosity 20 to 150 seconds, and a slope value of from 1 to 45 unitswhenv 25 grams of the productare .dispersed in 450 ml. of water at 80 F;

erate this'invention, although it is understood that this invention is not limited thereby, are that the'waxy type starch be oxidized to the extent where it has a carboxyl concentration which falls within the range of 0.05 to: 0.12 It will then have a Scott viscosity which falls within the rangeof 40 to'70 seconds per 100 jmli'onthe basis of 12 grams of starch cooked in 280 m1. of'water for .15 minutes and within the range of 30 to 60 seconds per IOQ when cooked for minutes. It have'a paste periodof 16 hours slurry was neutralized by the addition of approximatelyassasoa a) to 80 F. which falls within the light transmission using 13 mm.

for 60'minutes and stance is dispersed in waterto' a volume of 500 ml. The

preferred method is to oxidize the starch in its granule state followed by'washir'igthe' starch to remove soluble materials before the starch'i's g'elatin'iz'ed' It is preferable to use the salts of boric acid and borax together, in amounts ranging from'S to percent each based on starch dry substance. These salts may be added to the starch prior to oxidation but it is preferred that they are added after the starch is washed and they are cooked together. 7 p

' The paste may' be roll or spray dried. It is preferable to roll dry the paste and it is preferred that the flake product produced when ground has a funnel spectrophotometer at a; will have a Brabender. the range of 70 to 200 units at' which falls within the. range of 110' paste was maintained at dispersibility which falls within the range of 100 to 500 seconds per 7 200 ml. when 10 grams are dispersed in 400 ml. of water at 80 F. and Brabender'hydration characteristics which fall within 'thetfollowing. ranges: peak viscosity 150 to 600 units; time to reach peak viscosity 75 to 135 seconds, and a slope value of from 1 to 10 units when 25, grams are dispersed in 450 ml. of water at 80 F.

The inventionwill be further illustrated by the detailed examples which follow although it is to be understood the invention is ,not limited thereby.

EXAMPLE 1 Six moles of waxy grain sorghum starch at 10 percent moisture (1080 g.) was suspended in 1540 m1. of water. To this slurry was added 106.4 ml. of alkaline sodium hypochlorite solution whose concentration, by volume, was 9.03 percent available chlorine and 4.79 percent free sodium hydroxide. The sodium hypochlorite solution, diluted with one part of water, was added slowly to the slurry within a period of 10 minutes. The temperature of the slurry was held at 80 F. and it was agitated for a at which time excess chlorine in the 0.3 gram of sodiun'i bisulphite. The pH value of the slurry was adjusted from approximately 9.5 to 7.0 by the addition of 28 ml. of 2 N hydrochloric acid. The slurry I the starch was then dewatered on a Biichner funnel and product was washed with approximately 4 liters of cold water. The starch cake was dried by. conventional means to a moisture content of approximately 10 percent. An-' alyses of the purified, dried starch product are shown in Table I under Example I.

Approximately 1.8 moles of the oxidized waxy grain sorghum starch product (330 grams at 10 percent moisture) was suspended in 730 mli ofwarm'wat'erto 16 B6. in which was dissolved 23.8 grams of boric, acid and 14.8% grams of borax. The slurry was agitated and heated with: steam in a jacketed vessel to gelatiniie the starch. The: a temperature of 210 F. fora proximately 20 minutes when heating was stopped and a solution containing a dye color and a germicidal agent:. was added.

The hot paste was dried on counterrotating rolls (di-' meter '24 inches) at a steam pressure of 95 pisii; and at a roll speed of 5 r.p.m. The colored flake produced; was crushed, ground and screened to pass a 25 -mesh screen. 7

a The powder had the characteristics shown in Table lf- EXAMPLE 2 Example 2 was repeated except that the amount of alkaline sodium hypochlorite solution used was decreased to 74.6 ml. The purified starch product wasv roll-dried with the amounts of salts as shown in Example 2- Analyses of the starch product and of the: roll-dried product are shown in Table I.

EXAMPLE 4 Example 2 was repeated except that the amount of? alkaline sodium hypochlorite solution used was increased 1 to 149.1 mi. The purified starch product was roll-dried? with-the amounts of salts as shown in Example 2..

Analyses of the starch produet'and of the roll-driedi product are shown in Table I.v

EXAMPLE 5 Example 2 was repeated except that 63.1 grams of borax and 77.7 grams of boric acid were dissolvedin the Table I.-Characteristics of purified,v dried, alkaline sodium hypochlorite oxidized waxy grain' sorghum starch products and of roll-dried products produced therefrom Characteristics of Oxidized Starch Product Characteristics of Roll Dried Product Scott Viscosity, Brabender Vls- Brabcnder H drati 11 Cooking Tim Scott Paste cosity, 1 Hour Characteri tics Example Minutes Clarity, Percent Funnel Percent COOH Dispersl- Light bility 15 ,Trans- Sec.

' mission C. 50 C. 200 ml. Peak Vis- Sec. to Slopecosity Peak 94 300 350 0. 089 170 165 120 3. t 95 155 0. 092 330 ,210 75 6. 75 350 450 0.038 289 575 135 11. 8 94 70 O. 110- 250 '50 90 '1. 3 84 0.025 405- 210 80 3. 5 480 Y 90 5.0 1, 300 50 20 1. 0- 72 860 25 44 280 265 85 5.3

Concentration: 12 grams starch cooked in 280 m1. of water. t In 13 mm. cuvettes using a Model 14 Spectrophotometer .wa er.

f 8 Concentration: 50 grams starch dry concentrationz 10 gramsof product Concentration: 25 grams of product at a wavelength 0! 650 in; against substance dispersed in water to a volmne dispersedln 400 m1. of water at Sci-F W V i Y a I d1sperSedin450ml.ofwaterat80F. V

otsoomi.

water'before the starch was added and suspended. The amount of alkaline 'sodiumrhypochlorite solution-used was 53.2 ml. This reaction'product was purified by filtering the slurry, washing the starch product on the filter with cold water, resuspending the filter cake in fresh water, t

adjusting the pH value of the slurry to 7.0 then *refiltering the slurry and rewashing the cake with water. The purified starch product was roll-dried with 'the amounts of salts as shown in Example 2. Analyses of the starch product and of the roll-dried product are shown in Table I.

EXAMPLE 6 had the characteristics outlined in flable I and the similarity of these characteristics to those'of the roll-dried products prepared in the previous examples indicated that this product was equivalent.

EXAMPLE 7 Example 2 was repeated except that 23.8 grams of boric acid and 29.7 grams of borax were used. Analyses of the'roll-dried product is shown in TableI.

EXAMPLE 8 Example 2 was repeated except that 17.8 grams of boric acid and 14.8 grams of borax were used in preparing the roll-dried product. Analyses of this product is shown in Table I.

EXAMPLE9 ing from to pounds per square inch in from 30 to.

60 seconds. The paste was roll-dried directly as it issued from the Votator unit. Analyses of this roll-dried product are shown in Table I. A description of the Votator and its use is given in US. Patent 2,609,326 (Sept. 2, 1952).

The oxidized starch products and the cold water dispersible laundry starch products made in accordance with the present invention were evaluated both in accordance with certain standard testing and analyzing procedures, as well as by performance comparison with a commercial standard liquid laundry starch product and a commercial standard laundry starch product for cooking purposes which may be taken as representative of currently available commercial laundry starch products. The tests and factors used for evaluating the products of this invention include the following:

15 and 90 Scott viscosity determinations Scott and paste clarity determinations Brabender viscosity determinations Carboxyl determination Funnel dispcrsibility Brabender hydration characteristics Sizing and ironing evaluations Scott viscosity determinations (15 minutes) are made in accordance with the procedure outlined in Chemistry and Industry of Starch by R. W. Kerr, 2nd edition, pp. 119-121. The 90-minute Scott determinations are made accordingly, except that the time during which the paste is heated is extended from 15 minutes to 90 minutes.

Scott paste clarity determinations are made by placing the hot paste from the 15-minute Scott viscosity determination in a 13 mm. cuvette and cooling it to room temtransmission for the distilled water.

perature. cell andone containing distilled water,

is placed in a Model -14 Coleman spectrophotometer.

The instrument is adjusted .toi'transmit monochromatic light at a wavelength of 650 'mr'and set at 100 percent The cell containing the starch paste is shifted into place. ,The amount of light passing through the paste is read directly from the scale of the instrument and reported -as percent light transmission against distilled water.

Barbender viscosity. determinations are made in-accordance with the procedure outlined in Chemistry and Industry of Starch by R. W. Kerr, 2nd edition, pp. 127 130, with the modifications that .grams dry substance-starch'is'dispersed in water to a volume of 500 ml. :Also the heating time'lat a temperature-of 95 C. and the holding time at a temperature of-50 C. is extended to minutes.

Carboxyl determinations 'garema'de when the oxidized starch product is demineralized by steeping in a dilute solution of a mineral-acid. Thereafter, the starch is fre'edof the acidby filtration and washing. Then, the

oxidized starch containing-the carboxyl .group in acid form is gelatinized'in hotw'ater and titrated with standard caustic solution using phenolphthalein as anindicator.

Funnel dispcrsibility determinations are. made according to the procedure outlined in US. Patent No. Re. 23,952 (Feb. 22,1955) with'the following modifications: Ten grams of the cold water dispersible starch product are dispersed .in-400-ml. of water. 'The time required for 200 m1. of the dispersion to pass through the funnel is considered the dispcrsibility rating of the product.

Brabender hydration characteristics of cold water dispersible starch products are measured as follows: A 25 gram sample of the test starch product is shaken in 450 ml. of water at a temperature of 80 F. for a short time to disperse it. The dispersion is quickly transferred to the cup of a Brabender amylograph (see references above), and maintained at a temperature of 80 F. The mechanism is turned on and allowed to operate for 20 minutes. The rate and manner by which the test product absorbs water is traced as a curve by the Brabender pen on the graph paper. The height of the curve is taken as the peak viscosity of the test product. This value and the time required to reach the peak value are both recorded. The slope of the traced curve connecting the origin with the peak viscosity point is calculated and also recorded.

The following description will illustrate how the sizing and ironing characteristics of the starch products of this invention are evaluated:

Eighty grams of the roll-dried product prepared in Example 1 was shaken for approximately 5 seconds with one quart of water. The product was freely dispersible in the water and no lumps were formed. The translucent, colored liquid starch product remained stable and mold free for a period of over one month at room temperature.

An additional quantity of liquid laundry starch was prepared in the above manner and diluted with two parts of water. The resultant liquid was used to size clothing. A commercially available, well-known brand of liquid laundry starch was obtained. Following package directions, it was diluted with two parts of water and the diluted suspension was used to size clothing similar in nature to those used with the test product. The garments were then dried, sprinkled and ironed following conventional procedures.

Both sets of garments ironed with equal facility and a smooth, pliable finish was given to the clothing. No sticking to the iron or flaking or masking occurred on cloth with the use of the test starch product. The garments sized with the test product were as full-bodied as those sized with the commercial liquid laundry starch product.

The above evaluation was repeated except that in place of the commercial liquid laundry starch product used in that example, a cooked paste of a commercially available, well-known brand of laundry starch (Linit) was used. 'A paste of this was made by slurrying 20 grams of starch in a srhall quantity of water to'whichwas then added 900 r nL'of boiling water. The paste, when cool, was used to'sizei clothing sirnilar iii nature to those used with the test product: sprinkled and ironed;

The garments were dried, Both sets of garmentsironed withe'qua1 facility and 'a smo th pIiabIe'finish' was given to the clothing. The

garments-sized with the test-product were as full-bodied as those sized with the cooked laundry starch product.

Iclaitn: t g 1.' A process for-makings cold water dispersible dry :laundry starch concentrate which-is quickly dispersible in cold-water withoutf cooking to 'form a stable laundry starch preparation which comprises preparing an aqueous suspension-ofgranules of a waxy grain starch selected from the group consisting of waxy grain sorghum starch, waxy maizestarch, and waxy rice starch, adding an' alkali metal hypochlorite to said suspension in an amount, based on. the dry weight of said starch,iequiva1ent to oxidize said starch to a carboxyl 'contentoffrom 0.025 to 0.12

percenuheating said suspension to oxidize said starch and provide a'paste having a-Scottviscosity within the range of 40 to 120 secondslper 100 mlfon the basis of 1').

grams of' said starch cooked in 280 ml. of; water for 15 minutes, neutralizing the excess chlorine said suspension, washing said oxidized starch, gelatinizing said 'oxistarch, "rapidly drying said oxidized starch and 20 :RC. i

water at 80 F.

grinding said dried oxidized star h, said oxidized starch beingdried in admixture-with 5 to ;20 percentby weight,

based-on the dry weight ofthe oxidized starch, of 'a compound selected from the group consisting of borax,

boric acid and mixtures thcreof;.said d.tied oxidized starch product having a carboxyl content of from 0.025 to 0.12 ;percent, a funnel dispersibility in the range of 70 to 1300 l seconds per 200 ml. 'of 10 grams dispersed in 400 ml. i of water at-80 F; and Brabender hydration characteristics in the range of peakyiscosity 50 to 600 units, time to reach peak viscosity 75 to B5 seconds, and a slope value of 1 to 45 units with 25 grams dispersed in 450 m1. of

, 2. A cold water dispersihle dry laundry starch concentrateprepared according to the process of claim 1. References Cited in' file' 'of 'this patent UNITED STATES PATENTS w V 7 OTHER REFERENCES Schopmeyer et a1. J. Ind. & Eng. Cheh'1., 35,. pages 1168-1172 (1943). r 

1. A PROCESS FOR MAKING A COLD WATER DISPERSIBLE DRY LAUNDRY STARCH CONCENTRATE WHIC IS QUICKLY DISPERSIBLE IN COLD WATER WITHOUT COOKING TO FORM A STABLE LAUNDRY STARCH PREPARATION WHICH COMPRISES PREPARING AN AQUEOUS SUSPENSION OF GRANULES OF A WAXY GRAIN STARCH SELECTED FROM THE GROUP CONSISTING OF WAXY GRAIN SORGHUM STARCH, WAXY MAIZE STARCH, AND WAXY RICE STARCH, ADDING AN ALKALI METAL HYPOCHLORITE TO SAID SUSPENSION IN AN AMOUNT, BASED ON THE DRY WEIGHT OF SAID STARCH, EQUIVALENT TO OXIDIZE SAID STARCH TO A CARBOXYL CONTENT OF FROM 0.025 TO 0.12 PERCENT, HEATING SAID SUSPENSION TO OXIDIZE SAID STARCH AND PROVIDE A PASTE HAVING A SCOTT VISCOISITY WITHIN THE RANGE TO 40 TO 120 SECONDS PER 100 ML. ON THE BASIS OF 12 GRAMS OF SAID STARCH COOKED IN 280 ML. OF WATER FOR 15 MINUTES, NEUTRALIZING THE EXCESS CHLORINE IN SAID SUSPENSION, WASHING SAID OXIDIZED STARCH, GELATINIZING SAID OXIDIZED STARCH, RAPIDLY DRYING SAID OXIDIZED STARCH AND GRINDING SAID DRIED OXIDIZED STARCH, SAID OXIDIZED STARCH BEING DRIED IN ADMIXTURE WITH 5 TO 20 PERCENT BY WEIGHT BASED ON THE DRY WEIGHT OF THE OXIDIZED STARCH, OF A COMPOUND SELECTED FROM THE GROUP CONSISTING OF BORAX, BORIC ACID AND MIXTURES THEREOF, SAID DRIED OXIDIZED STARCH PRODUCT HAVING A CARBOXYL CONTENT OF FROM 0.025 TO 0.12 PERCENT, A FUNNEL DISPERSIBILITY IN THE RANGE OF 70 TO 1300 SECONDS PER 200 ML. OF 10 GRAMS DISPERSED IN 400 ML. OF WATER AT 80*F. AND BRABENDER HYDRATION CHARACTERISTICS IN THE RANGE OF PEAK VISCOSITY 50 TO 600 UNITS, TIME TO REACH PEAK VISOCITY 75 TO 135 SECONDS, AND A SLOPE VALUE OF 1 TO 45 UNITS WITH 25 GRAMS DISPERSED IN 450 ML. OF WATER AT 80*F. 